Emerging predictors of the response to the blockade of immune checkpoints in cancer therapy

Checkpoint blockade-based immunotherapy offers new options and powerful weapons for the treatment of cancer, but its efficacy varies greatly among different types of cancer and across individual patients. Thus, the development of the right tools that can be used to identify patients who could benefit from this therapy is of utmost importance in order to maximize the therapeutic benefit, minimize risk of toxicities, and guide combination approaches. Multiple predictors have emerged that are based on checkpoint receptor ligand expression, tumor mutational burden, neoantigen and microsatellite instability, tumor-infiltrating immune cells, and peripheral blood biomarkers. In this review, we discuss the current state and progress of predictors as aids in checkpoint blockade-based immunotherapy in cancer.